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Mon, 24 Feb 2020 14:54:38 -0800 (PST) Subject: Re: [PATCH v4 0/3] io_uring: add splice(2) support From: Pavel Begunkov To: Jens Axboe , Alexander Viro , Stefan Metzmacher , io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org References: <923cc84a-e11f-2a16-2f12-ca3ba2f3ade4@kernel.dk> <596e6b61-e9de-7498-05c4-571613673c15@kernel.dk> Autocrypt: addr=asml.silence@gmail.com; prefer-encrypt=mutual; keydata= mQINBFmKBOQBEAC76ZFxLAKpDw0bKQ8CEiYJRGn8MHTUhURL02/7n1t0HkKQx2K1fCXClbps bdwSHrhOWdW61pmfMbDYbTj6ZvGRvhoLWfGkzujB2wjNcbNTXIoOzJEGISHaPf6E2IQx1ik9 6uqVkK1OMb7qRvKH0i7HYP4WJzYbEWVyLiAxUj611mC9tgd73oqZ2pLYzGTqF2j6a/obaqha +hXuWTvpDQXqcOZJXIW43atprH03G1tQs7VwR21Q1eq6Yvy2ESLdc38EqCszBfQRMmKy+cfp W3U9Mb1w0L680pXrONcnlDBCN7/sghGeMHjGKfNANjPc+0hzz3rApPxpoE7HC1uRiwC4et83 CKnncH1l7zgeBT9Oa3qEiBlaa1ZCBqrA4dY+z5fWJYjMpwI1SNp37RtF8fKXbKQg+JuUjAa9 Y6oXeyEvDHMyJYMcinl6xCqCBAXPHnHmawkMMgjr3BBRzODmMr+CPVvnYe7BFYfoajzqzq+h EyXSl3aBf0IDPTqSUrhbmjj5OEOYgRW5p+mdYtY1cXeK8copmd+fd/eTkghok5li58AojCba jRjp7zVOLOjDlpxxiKhuFmpV4yWNh5JJaTbwCRSd04sCcDNlJj+TehTr+o1QiORzc2t+N5iJ NbILft19Izdn8U39T5oWiynqa1qCLgbuFtnYx1HlUq/HvAm+kwARAQABtDFQYXZlbCBCZWd1 bmtvdiAoc2lsZW5jZSkgPGFzbWwuc2lsZW5jZUBnbWFpbC5jb20+iQJOBBMBCAA4FiEE+6Ju PTjTbx479o3OWt5b1Glr+6UFAlmKBOQCGwMFCwkIBwIGFQgJCgsCBBYCAwECHgECF4AACgkQ Wt5b1Glr+6WxZA//QueaKHzgdnOikJ7NA/Vq8FmhRlwgtP0+E+w93kL+ZGLzS/cUCIjn2f4Q Mcutj2Neg0CcYPX3b2nJiKr5Vn0rjJ/suiaOa1h1KzyNTOmxnsqE5fmxOf6C6x+NKE18I5Jy xzLQoktbdDVA7JfB1itt6iWSNoOTVcvFyvfe5ggy6FSCcP+m1RlR58XxVLH+qlAvxxOeEr/e aQfUzrs7gqdSd9zQGEZo0jtuBiB7k98t9y0oC9Jz0PJdvaj1NZUgtXG9pEtww3LdeXP/TkFl HBSxVflzeoFaj4UAuy8+uve7ya/ECNCc8kk0VYaEjoVrzJcYdKP583iRhOLlZA6HEmn/+Gh9 4orG67HNiJlbFiW3whxGizWsrtFNLsSP1YrEReYk9j1SoUHHzsu+ZtNfKuHIhK0sU07G1OPN 2rDLlzUWR9Jc22INAkhVHOogOcc5ajMGhgWcBJMLCoi219HlX69LIDu3Y34uIg9QPZIC2jwr 24W0kxmK6avJr7+n4o8m6sOJvhlumSp5TSNhRiKvAHB1I2JB8Q1yZCIPzx+w1ALxuoWiCdwV M/azguU42R17IuBzK0S3hPjXpEi2sK/k4pEPnHVUv9Cu09HCNnd6BRfFGjo8M9kZvw360gC1 reeMdqGjwQ68o9x0R7NBRrtUOh48TDLXCANAg97wjPoy37dQE7e5Ag0EWYoE5AEQAMWS+aBV IJtCjwtfCOV98NamFpDEjBMrCAfLm7wZlmXy5I6o7nzzCxEw06P2rhzp1hIqkaab1kHySU7g dkpjmQ7Jjlrf6KdMP87mC/Hx4+zgVCkTQCKkIxNE76Ff3O9uTvkWCspSh9J0qPYyCaVta2D1 Sq5HZ8WFcap71iVO1f2/FEHKJNz/YTSOS/W7dxJdXl2eoj3gYX2UZNfoaVv8OXKaWslZlgqN jSg9wsTv1K73AnQKt4fFhscN9YFxhtgD/SQuOldE5Ws4UlJoaFX/yCoJL3ky2kC0WFngzwRF Yo6u/KON/o28yyP+alYRMBrN0Dm60FuVSIFafSqXoJTIjSZ6olbEoT0u17Rag8BxnxryMrgR dkccq272MaSS0eOC9K2rtvxzddohRFPcy/8bkX+t2iukTDz75KSTKO+chce62Xxdg62dpkZX xK+HeDCZ7gRNZvAbDETr6XI63hPKi891GeZqvqQVYR8e+V2725w+H1iv3THiB1tx4L2bXZDI DtMKQ5D2RvCHNdPNcZeldEoJwKoA60yg6tuUquvsLvfCwtrmVI2rL2djYxRfGNmFMrUDN1Xq F3xozA91q3iZd9OYi9G+M/OA01husBdcIzj1hu0aL+MGg4Gqk6XwjoSxVd4YT41kTU7Kk+/I 5/Nf+i88ULt6HanBYcY/+Daeo/XFABEBAAGJAjYEGAEIACAWIQT7om49ONNvHjv2jc5a3lvU aWv7pQUCWYoE5AIbDAAKCRBa3lvUaWv7pfmcEACKTRQ28b1y5ztKuLdLr79+T+LwZKHjX++P 4wKjEOECCcB6KCv3hP+J2GCXDOPZvdg/ZYZafqP68Yy8AZqkfa4qPYHmIdpODtRzZSL48kM8 LRzV8Rl7J3ItvzdBRxf4T/Zseu5U6ELiQdCUkPGsJcPIJkgPjO2ROG/ZtYa9DvnShNWPlp+R uPwPccEQPWO/NP4fJl2zwC6byjljZhW5kxYswGMLBwb5cDUZAisIukyAa8Xshdan6C2RZcNs rB3L7vsg/R8UCehxOH0C+NypG2GqjVejNZsc7bgV49EOVltS+GmGyY+moIzxsuLmT93rqyII 5rSbbcTLe6KBYcs24XEoo49Zm9oDA3jYvNpeYD8rDcnNbuZh9kTgBwFN41JHOPv0W2FEEWqe JsCwQdcOQ56rtezdCJUYmRAt3BsfjN3Jn3N6rpodi4Dkdli8HylM5iq4ooeb5VkQ7UZxbCWt UVMKkOCdFhutRmYp0mbv2e87IK4erwNHQRkHUkzbsuym8RVpAZbLzLPIYK/J3RTErL6Z99N2 m3J6pjwSJY/zNwuFPs9zGEnRO4g0BUbwGdbuvDzaq6/3OJLKohr5eLXNU3JkT+3HezydWm3W OPhauth7W0db74Qd49HXK0xe/aPrK+Cp+kU1HRactyNtF8jZQbhMCC8vMGukZtWaAwpjWiiH bA== Message-ID: <189e8cb4-df3a-f12d-9b21-7134caa918bb@gmail.com> Date: Tue, 25 Feb 2020 01:53:55 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.3.0 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Ozoo4hy5KCIvsO7awHbFxR1uVzpAnLi9p" Sender: io-uring-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: io-uring@vger.kernel.org This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --Ozoo4hy5KCIvsO7awHbFxR1uVzpAnLi9p Content-Type: multipart/mixed; boundary="Aude6cfmBxHJCEFukhlDs0IzGgKB6pbmc"; protected-headers="v1" From: Pavel Begunkov To: Jens Axboe , Alexander Viro , Stefan Metzmacher , io-uring@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Message-ID: <189e8cb4-df3a-f12d-9b21-7134caa918bb@gmail.com> Subject: Re: [PATCH v4 0/3] io_uring: add splice(2) support References: <923cc84a-e11f-2a16-2f12-ca3ba2f3ade4@kernel.dk> <596e6b61-e9de-7498-05c4-571613673c15@kernel.dk> In-Reply-To: --Aude6cfmBxHJCEFukhlDs0IzGgKB6pbmc Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: quoted-printable On 25/02/2020 01:51, Pavel Begunkov wrote: > On 25/02/2020 01:34, Jens Axboe wrote: >> On 2/24/20 8:35 AM, Jens Axboe wrote: >>> On 2/24/20 1:32 AM, Pavel Begunkov wrote: >>>> *on top of for-5.6 + async patches* >>>> >>>> Not the fastets implementation, but I'd need to stir up/duplicate >>>> splice.c bits to do it more efficiently. >>>> >>>> note: rebase on top of the recent inflight patchset. >>> >>> Let's get this queued up, looks good to go to me. Do you have a few >>> liburing test cases we can add for this? >> >> Seems to me like we have an address space issue for the off_in and >=20 > Is that a problem? From the old fixing thread loop_rw_iter() it appeare= d > to me, that it's ok to pass a kernel address as a user one. > f_op->write of some implemented through the same copy_to_user(). Either I finally need to check myself how the protection is implemented..= =2E >=20 >> off_out parameters. Why aren't we passing in pointers to these >> and making them work like regular splice? >=20 > That's one extra copy_to_user() + copy_from_user(), which I hope to rem= ove > in the future. And I'm not really a fan of such API, and would prefer t= o give > away such tracking to the userspace. >=20 >> >> diff --git a/fs/io_uring.c b/fs/io_uring.c >> index 792ef01a521c..b0cfd68be8c9 100644 >> --- a/fs/io_uring.c >> +++ b/fs/io_uring.c >> @@ -448,8 +448,8 @@ struct io_epoll { >> struct io_splice { >> struct file *file_out; >> struct file *file_in; >> - loff_t off_out; >> - loff_t off_in; >> + loff_t __user *off_out; >> + loff_t __user *off_in; >> u64 len; >> unsigned int flags; >> }; >> @@ -2578,8 +2578,8 @@ static int io_splice_prep(struct io_kiocb *req, = const struct io_uring_sqe *sqe) >> return 0; >> =20 >> sp->file_in =3D NULL; >> - sp->off_in =3D READ_ONCE(sqe->splice_off_in); >> - sp->off_out =3D READ_ONCE(sqe->off); >> + sp->off_in =3D u64_to_user_ptr(READ_ONCE(sqe->splice_off_in)); >> + sp->off_out =3D u64_to_user_ptr(READ_ONCE(sqe->off)); >> sp->len =3D READ_ONCE(sqe->len); >> sp->flags =3D READ_ONCE(sqe->splice_flags); >> =20 >> @@ -2614,7 +2614,6 @@ static int io_splice(struct io_kiocb *req, struc= t io_kiocb **nxt, >> struct file *in =3D sp->file_in; >> struct file *out =3D sp->file_out; >> unsigned int flags =3D sp->flags & ~SPLICE_F_FD_IN_FIXED; >> - loff_t *poff_in, *poff_out; >> long ret; >> =20 >> if (force_nonblock) { >> @@ -2623,9 +2622,7 @@ static int io_splice(struct io_kiocb *req, struc= t io_kiocb **nxt, >> flags |=3D SPLICE_F_NONBLOCK; >> } >> =20 >> - poff_in =3D (sp->off_in =3D=3D -1) ? NULL : &sp->off_in; >> - poff_out =3D (sp->off_out =3D=3D -1) ? NULL : &sp->off_out; >> - ret =3D do_splice(in, poff_in, out, poff_out, sp->len, flags); >> + ret =3D do_splice(in, sp->off_in, out, sp->off_out, sp->len, flags);= >> if (force_nonblock && ret =3D=3D -EAGAIN) >> return -EAGAIN; >> =20 >> >=20 --=20 Pavel Begunkov --Aude6cfmBxHJCEFukhlDs0IzGgKB6pbmc-- --Ozoo4hy5KCIvsO7awHbFxR1uVzpAnLi9p Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEE+6JuPTjTbx479o3OWt5b1Glr+6UFAl5UVAMACgkQWt5b1Glr +6U6cQ/+OtaKdH4Wn7/s7+vEyidYyGSmLFzAVj/WPBXzP7nYlZpgXPoQ45knUbus roj7NcE0rj9ZPk8FUgfnkI51KeJH0jc2pAroYUEYkBprCvUSTTRLzH9fFeB9UZmg +mdhrETW/FMqLKY6PQ85ydTwXpnF38c2CPoT/QaxOz7YOMwDlIc4zmVMy86jkgw1 e8N7C7Xd4POlAOfpTGwIXTCvBapVVjVfZ5vvKLapYHiQVo4Cmt6/8QH0fDIC1LNq azwTfPmAnTzYywLQb/HiAU/MzcIBYKrxlSdsMu20iH69UvxJmdzJx3XrG1cYbpok PA/OVSq+kncEezoQdNXV7/r/ETBHfG7Tqt8MprzGpHJH28bygwiSu1mrsGRAaH6t 4ULG1Z2J+JjGjLUcm2TLsKH7rDTFRh4zACJQl2zl9Iwhdwa+wVV8ZnKcAw+mNTR/ nN74hYsn1UncSwGO9/ydeR+Tg4tB8gjXApeVzGPx9Tuf2ukGpgVNFlAYYjdT70ZN d9upyg/9yIuQMVL+5XGd4t9zVRbTdsTsZcfTjTzl1zyzm98Em6lumgsQAkyF9rGf zMF5C2Qj6IbBN/bJUcgSqMUWMYkn+IoP4eZQoZcctbV8PdQEYMc9Yi+b1Zf80MR/ FK6mR8GMCFsz2WHTif+0h0jj4WPyqpmUcBXxe0zfKivfNCgUuQE= =VNrk -----END PGP SIGNATURE----- --Ozoo4hy5KCIvsO7awHbFxR1uVzpAnLi9p--